Rigid Body Simulations never work- everything flies in random directions
This one is rigged, not physic'd.  (I've treated it as a lock)
(Blend file below)

The bones are pulled in reverse to guarantee the locking shaft will move in a dead straight line.
To this end an Empty is animated to the left and is a parent for the shaft.  It's also an IK target for the bone that controls the middle linkage.
As it moves it pulls that bone across to effectively rotate the 1st child-bone that parents the disc, forcing it to rotate also.
It's all done back to front but as far as I can make out, it's the only practical way to guarantee the locking shaft won't vary from it's straight path.
As you've come to realise, Blender is an animator/modeller, not an engineering tool and does require some innovation to get around it's physics limitations at times.  It can be a marvelous brain stimulator!